1. Field of the Invention
The present invention relates to a technique for obtaining information on an electrical characteristic of a sample to be measured, and particularly to a novel technique for measuring the permittivity of a sample at a minute fault part formed in a conductor layer part of a transmission line having a predetermined structure.
2. Description of the Related Art
There are various measuring techniques for determining the properties (for example a chemical structure and an internal structure) of a substance. For example, the permittivity (dielectric permittivity) of a substance can be an important property value in determining the properties (for example a chemical structure and an internal structure) of the substance. A dielectric measurement method is carried out in a frequency domain using an impedance analyzer or a network analyzer. There is also a method of converting data measured in a time domain using time domain reflectometry (TDR method) into a frequency domain by Fourier analysis or the like. Recently, attenuated total reflection spectroscopy (ATR method) has been proposed as a permittivity measuring method. Japanese Patent Laid-Open No. 2002-286632 discloses an example of the technique.
In related art, methods widely and generally used when the permittivity (dielectric spectrum) of a sample is to be measured include for example methods in which the target sample is measured in a state of being interposed between two electrodes in the form of a capacitor, the sample is measured after being injected into a space including an electrode in a cylindrical shape or a coaxial shape, and measurement is performed with a termination type electrode soaked in a container containing the sample.
Sample quantities necessary in such existing permittivity measuring methods are 100 μL or more, excluding a case of a macromolecule that can form a thin film, for example. Therefore, such existing permittivity measuring methods are fundamentally unsuitable for measurement of a precious sample. In a case of measuring a liquid sample using an electrode in a coaxial shape, a sample in a quantity of about 40 μL can be measured. However, this electrode is unsuitable for measurement of a sample other than a liquid (for example a sample in the form of a gel). In addition, any of the above-described existing methods requires skills to prevent the mixing in of air bubbles when injecting a sample, and thus has a limited potential for development into automatic measurement techniques.
In addition, with ideas as an extension of the existing permittivity measuring methods, it is difficult to realize a compact measuring device because there are limitations to the size and shape of the electrode itself and the like.